Understand the functions of the digestive system

2.08 Understand the functions of the Digestive System Essential questions What are the functions of the digestive system? How do the functions of chemical and physical digestion interrelate? 2.08 Understand the functions and disorders of the digestive system 2

Functions of the digestive system 2.08 Understand the functions and disorders of the digestive system 3

Functions of the digestive system Mouth (buccal cavity) Food enters digestive system through mouth Inside of the mouth is covered with mucous membranes Roof of mouth is HARD PALATE (bone) and soft palate Uvula flap that hangs off soft palate prevents food from going up the nose when you swallow What is bolus? Bolus is a ball of food that has just been chewed

Functions of the digestive system Tongue Helps in chewing and swallowing Made of skeletal muscle attached to four bones Taste buds on the surface 2.08 Understand the functions and disorders of the digestive system 5

Functions of the digestive system Teeth Mastication, a.k.a chewing teeth help in mechanical digestion How is the tooth’s shape related to its function? Incisors - have sharp edges for biting Cuspids - flat top and are used for grinding Bicuspids - are pointed and like a nutcracker to grind food Molars - designed for crushing 2.08 Understand the functions and disorders of the digestive system 6

Functions of the digestive system Salivary glands Secrete saliva Chemical action takes place as a result of saliva Amylase, mucin and ptyalin are enzymes that start chemical breakdown of food Ptyalin converts starches into simple sugar 7

Functions of the digestive system Palate Separates mouth and sinuses Uvula Prevents food from going into the nasal cavity when swallowing 2.08 Understand the functions and disorders of the digestive system 8

Functions of the digestive system Pharynx Passageway (tube) for food, liquids and air 2.08 Understand the functions and disorders of the digestive system 9

Functions of the digestive system Esophagus Passageway for food and liquids only What is its relevance to your health? 2.08 Understand the functions and disorders of the digestive system 10

Functions of the digestive system Stomach Functions of the stomach: Chemical digestion occurs with gastric (digestive juices) Mechanical digestion occurs with stomach walls churning and mixing This mixture is called Chyme

Functions of the digestive system Stomach How long does it take for stomach to empty? Takes 2-4 hours for stomach to empty Small amount of chyme enters duodenum a little at a time which is controlled by the pyloric sphincter

Functions of the digestive system Gastric juices (chemicals) used in digestion Enteroendocrine glands gastrin Parietal cells HCL and intrinsic factor Chief type cells pepsinogen Mucus cells alkaline mucus Rennin 13

Functions of the digestive system Small Intestine Digestion is completed and absorption occurs. Addition of enzymes pancreas which produces insulin bile produced by liver/gallbladder 14

Functions of the digestive system Small Intestine Villi: Projections that look like hair that add more surface room and absorb the nutrients 15

Functions of the digestive system Small Intestine Relevance to your health Absorb most of the nutrients 16

Functions of the digestive system Pancreas Function of digestive enzymes secreted by the pancreas? Lipase - breaks down lipids Amylase - breaks down starches Trypsin - breaks down proteins 17

Functions of the digestive system Pancreas Pancreas is a gland of the endocrine system secreting insulin which regulates the homeostasis of sugar (glucose) in the blood. Which other system does the pancreas function? 18

Functions of the digestive system Liver Functions: Produces and stores glucose in the form of glycogen Detoxify alcohol, drugs and other harmful substances Manufactures blood proteins Manufactures bile which breaks down fats 19

Functions of the digestive system Liver What is the function of Bile - breaks down fats Glycogen - easily broken down to glucose for immediate use for the cells What vitamin is produced by the liver? Vitamin D The liver stores Vitamin A, D and B complex All necessary for production of red blood cells 20

Functions of the digestive system Gallbladder Small green organ, inferior surface of the liver Stores and concentrates bile until needed by the body When fatty foods digested, bile is released by the gallbladder Bile flows into small intestine at the duodenum 2.08 Understand the functions and disorders of the digestive system 21

Functions of the digestive system Large intestine Absorb liquids from Chyme, concentrating to what you know as stool Relevance to health: allows for absorption of fluids and micromolecules to aid in homeostasis Type of diet promotes colon health: High in fiber What is chyme? What is the semi-solid liquid secreted from the ileum through the ileoceccal valve called that enters the large intestine? 22

Functions of the digestive system Large intestine Approximately 2 inches in diameter a.k.a. the colon Cecum - lower right portion of large intestine Appendix - flinger like projection of the cecum Rectum - last portion of large intestine - where stool is stored Anus - external opening 23

Functions of the digestive system What can healthcare professionals learn from observing stool specimens? Blood Undigested food Mucous Strange color or shape On average, how much flatus does a person produce per day? 1-3 pints / day pass through rectum, bacteria produce the gas

Functions of the digestive system News Flash... New treatment!!!! Fecal transplant Allows the bacteria from the healthy stool to repopulate the gut of the patient who has lost healthy bacteria in their gut Used to treat Clostridium difficile that grows in human intestines Symptoms range from persistent diarrhea to life- threatening inflammation of the colon to death 2.08 Understand the functions and disorders of the digestive system 25

Functions of the digestive system Discuss the processes of digestion and their relevance to health. Chemical: mouth and stomach, limited in small intestine Physical: mouth and stomach Absorption of nutrients: small intestine Absorption of fluids: large intestine Elimination: large intestine (rectum and anus) 2.08 Understand the functions and disorders of the digestive system 26

2.08 Understand the functions and disorders of the digestive system Act of Digestion Each action of the digestive system… 6 actions Ingestion: the taking in of food or liquids saliva softens food to make it easier to swallow Ptyalin in saliva converts starches into simple sugar Under nervous control - just thinking of food can cause your mouth to water 2.08 Understand the functions and disorders of the digestive system 27

2.08 Understand the functions and disorders of the digestive system Act of Digestion Each action of the digestive system… 6 actions Mastication is the process of chewing up food creates a bolus which is a soft, pliable ball created from chewing and and the addition of saliva which slides down esophagus 2.08 Understand the functions and disorders of the digestive system 28

2.08 Understand the functions and disorders of the digestive system Act of Digestion Each action of the digestive system… 6 actions Digestion is the breaking down of food for the body’s use Gastric juices are released for chemical digestion Stomach walls churn and mix this mixture becomes chyme Small amount of chyme enters duodenum a little at a time which is controlled by the pyloric sphincter Takes 2-4 hours for the stomach to empty 2.08 Understand the functions and disorders of the digestive system 29

2.08 Understand the functions and disorders of the digestive system Act of Digestion Each action of the digestive system… 6 actions Secretion is digestive enzymes are secreted to break down different types of food of enzymes secreted in liver, gallbladder and pancreas. These secretions aid in completing digestion 2.08 Understand the functions and disorders of the digestive system 30

2.08 Understand the functions and disorders of the digestive system Act of Digestion Each action of the digestive system… 6 actions Absorption is taking in nutrients to feed the body 2.08 Understand the functions and disorders of the digestive system 31

Act of Digestion Each action of the digestive system… 6 actions Excretion is to take things out of the body that are not usable occurs in large intestine. Bacterial action on undigested food - decomposed products excreted through colon Bacterial form moderate amounts of B complex and vitamin K Bacteria produce gas which accumulates and is released through rectum Feces are undigested semi-solid consisting of bacteria, waste products, mucous and cellulose 32

Functions of the digestive system Check your knowledge… 33